1. Field of the Invention
The present invention relates to an on vehicle tire air pressure detecting device and a cast wheel for mounting the device. In particular, the present invention is directed to an on vehicle tire air pressure detecting device and a cast wheel which is capable of preventing the device from interfering with bead sections of a tire when the tire is assembled to the cast wheel or the tire is removed from the cast wheel.
2. Description of Background Art
An on vehicle tire air pressure detecting device for detecting whether air pressure of a vehicular tire is low or not is known, for example, from Japanese Unexamined Patent Publication H10-44726, entitled xe2x80x9cTIRE AIR PRESSURE WARNING DEVICE.xe2x80x9d
In FIG. 1 of the patent publication described above, a state in which a tire air pressure warning device which includes a transmission section 7 and a valve stem 10 are mounted on a wheel rim 1 by a nut 9 is disclosed.
In an art of the patent publication described above, if a case 2 of the tire air pressure warning device projects from a side of the tire, when assembling the tire on a wheel rim 1, bead sections of the tire interfere with the case 2.
Thus, an object of the present invention is to prevent bead sections of a tire from interfering with an on vehicle tire air pressure detecting device when assembling the tire on a cast wheel, or removing the tire from the cast wheel.
In order to achieve the object described above, a first aspect of the present invention is directed to a tire air pressure detecting device for detecting tire air pressure by an air pressure sensor mounted on a rim of a vehicular cast wheel, wherein a rim drop section, dented in a shape of a ring, is provided on inner sides of bead seat sections of a rim for holding bead sections of the tire. In addition, a recessed section is provided in the rim drop section, and an air pressure sensor is accommodated in the recessed section.
By accommodating the air pressure sensor in the recessed section of the rim, when the tire is assembled on the cast wheel by utilizing a tire changer or the like, or the tire is removed from the cast wheel, the bead sections of the tire are prevented from interfering with the air pressure sensor, and damage of the air pressure sensor is prevented.
According to a second aspect of the present invention, a tire air pressure detecting device is provided for detecting tire air pressure by an air pressure sensor mounted on a rim of a vehicular cast wheel, wherein, the air pressure sensor is formed in a shape of a curve along an inner side surface of the rim.
By providing the air pressure sensor in the shape of a curve along the inner side surface of the rim, and by eliminating a projecting section of the air pressure sensor to the tire side, when the tire is assembled on the cast wheel, or is removed from the cast wheel, the bead sections of the tire are prevented from interfering with the air pressure sensor, and damage of the air pressure sensor is prevented.
According to a third aspect of the present invention, a weight section is integrally molded with the rim for being easily balanced with the air pressure sensor at a position shifted at an angle of 180xc2x0 to a peripheral direction from a position where the air pressure sensor is mounted on the rim.
With the above construction of the integrally molded weight section, a cast wheel is easily balanced, the necessity to mount or to affix a specific weight to the cast wheel to balance the wheel is eliminated, and workability is improved.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.